[unreadable] It is proposed to develop a non-invasive thermal system for quantitative measurement of blood perfusion. The main goal is to design and build a clinical device that will be easy to use, automated and accurate for a wide variety of applications. Two different preliminary designs will be developed and tested to demonstrate their different features of operation and safety. Because blood perfusion represents the local, multi-directional blood flow through capillaries and intracellular spaces of living tissue, it is difficult to quantify with absolute values. Consequently, a second goal is to develop a standard in-vitro system for absolute calibration of perfusion measurement systems. Two different proposed thermal systems will be compared along with a laser Doppler system in this calibration device to determine performance against an absolute standard. The measurement systems will also be compared by testing in vivo in rats. At the end of this two year project a calibration system and two measurement systems will have been designed, built, and tested. Based on their assessed performance the appropriate applications will be pursued in future studies using the resources of the Veterinary School, the Wake Forest Medical School and the Carilion Biomedical Institute affiliated with Virginia Tech. [unreadable] [unreadable]